The present invention relates to a radio communication system and destination portable terminal time identification method capable of identifying the time of a destination portable telephone terminal in advance by an originating portable telephone terminal.
In wire telephone terminals and telephone networks, a telephone number containing a toll number is assigned in association with an area where a telephone terminal is installed. For international direct distance dialing, the preassigned country code of a destination must be dialed. In wire telephone terminals, their installation locations are fixed, and telephone numbers are assigned in correspondence with the installation locations. In calling a destination telephone terminal, the area and time zone (time difference) where the destination telephone terminal exists must be identified from the destination telephone number containing a toll number and country code.
In a so-called portable telephone system in which a telephone terminal and base station are connected by radio and communicate with each other, a portable telephone terminal can move geographically. For this reason, an area where the portable telephone terminal is located cannot be identified from a telephone number assigned to the portable telephone terminal. In calling a portable telephone terminal usable over a plurality of countries by so-called international roaming or the like, the originating side cannot determine the origination time in consideration of the time difference from the terminating portable telephone terminal in advance. The same problem occurs in a country such as USA which has a plurality of time zones.